1. Field of the Invention
This invention relates to an air conditioning apparatus for distributing conditioned air into a plurality of rooms through a duct.
2. Description of the Related Art
A building or the like having a plurality of rooms uses an air conditioning apparatus for obtaining conditioned air (cool or warm air) by operating a refrigerating cycle and a fan, and supplying the air to the rooms through a duct.
U.S. Pat. No. 5,004,149 discloses such a duct-type air conditioning apparatus. The disclosed apparatus has a duct with a plurality of air passages diverging into rooms. Each air passage has a damper. The thermal load in each room is detected, and the required amount of conditioned air in the room is determined based on the detected thermal load. The opening degree of the damper is controlled based on the required amount of conditioned air, thereby supplying the same into each room.
Another duct-type air conditioning apparatus is disclosed in Published Unexamined Japanese Patent Application No. 3-164647. In this apparatus, a heat exchanger and a damper are provided in each air passage of a duct. The duct has a fan for sucking air into the duct. The sucked air is cooled or heated by the heat exchanger, thus becoming conditioned air. The conditioned air is blown into each room when the damper is open.
A multi-type air conditioning apparatus as an apparatus for performing air conditioning of a plurality of rooms is known from Published Unexamined Japanese Application No. 64-57061. This apparatus comprises a single outdoor unit and a plurality of indoor units connected to the outdoor unit, and cooling operation and heating operation can simultaneously be performed in the rooms.
Some duct-type air conditioning apparatuses have the function of limiting the allowable minimum opening degree of a damper on the basis of a change in the opening degree thereof. The allowable minimum opening degree is a minimum value required for supplying air of an amount necessary to ventilate each room.
In the apparatus having the above-described function, supply of conditioned air is continued even after the room temperature reaches an optimal value. Thus, the room temperature may excessively be reduced during cooling, and may excessively be increased during heating.